1. Field of the Invention
The present invention relates to an imaging apparatus having a photosensor and a manufacturing method of the same.
2. Description of the Related Art
According to Jpn. Pat. Appln. KOKAI Publication No. 2010-56292, a glass plate having a lens is mounted on the lower surface of a photosensor via a frame-shaped spacer. In this case, the photosensor comprises a semiconductor substrate. A light receiving portion is provided in the center of the upper surface of the semiconductor substrate. A connection pad is provided in the peripheral part of the upper surface of the semiconductor substrate to be connected to the light receiving portion.
A wiring line is provided on the lower surface of the semiconductor substrate. For, for example, a CMOS, the wiring line is essential to extract a signal as a voltage. One end of the wiring line is connected to the connection pad via a piercing electrode provided within a through-hole which is provided in the peripheral part of the semiconductor substrate. An insulating film is provided on the lower surface of the semiconductor substrate except for a land of the wiring line. The land of the wiring line is exposed through an opening provided in the insulating film. A solder ball is provided on the lower surface of the land of the wiring line exposed through the opening provided in the insulating film.
According to Jpn. Pat. Appln. KOKAI Publication No. 2010-56292, a semiconductor wafer greater in thickness than a semiconductor substrate of an imaging apparatus as a finished product is first prepared. In this case, a light receiving portion is provided in the center of the upper surface of an imaging apparatus formation region of the semiconductor substrate, around which a connection pad is provided to be connected to the light receiving portion.
Furthermore, a glass plate having the same size as the semiconductor wafer and having lenses provided on its lower surface is mounted on the semiconductor wafer via a lattice-shaped spacer. The lower side of the semiconductor wafer is then ground to reduce the thickness of the semiconductor wafer. A through-hole is then formed in the peripheral part within the imaging apparatus formation region of the semiconductor wafer. A wiring line and a piercing electrode are then formed on the lower surface of the semiconductor wafer including the inside of the through-hole by electrolytic plating.
An insulating film having an opening is then formed on the lower side of the semiconductor wafer. A solder ball is then formed on the lower surface of a land of the wiring line exposed through the opening of the insulating film. The semiconductor wafer, the lattice-shaped spacer, and a glass plate having the same size as the semiconductor wafer are then cut to obtain imaging apparatuses.
In the meantime, the problem of the above-mentioned conventional method of manufacturing the imaging apparatus is that the number of steps in the process of forming the through-hole in the peripheral part within the imaging apparatus formation region of the semiconductor wafer is relatively great. For example, the process includes the formation of a resist film on the lower surface of the semiconductor wafer, the formation of an opening in the resist film, the formation of the through-hole in the semiconductor wafer by etching that uses the resist film as a mask, and the detaching of the resist film. Moreover, before the step of grinding the lower side of the semiconductor wafer to reduce the thickness of the semiconductor wafer, the glass plate having the same size as the semiconductor wafer has to be disposed on the semiconductor wafer for reinforcement. This disadvantageously restricts a fabrication process.
It is therefore an object of the present invention to provide an imaging apparatus and a manufacturing method of the same that enable a reduction in the number of steps and also enables a fabrication process to be less restricted.